chime_15: Part of a set to blink every quarter-hour.

In Blink1Control, add IFTTT blink rule to match chime_15. I have my pattern set to Green for 2 seconds, then Off for 1 second. This may be used in a set with chime_15, chime_30, chime_45, and hour_chime. At chime_30 I have that same pattern play 2 times, and at chime_45 it plays 3 times.